In my earlier U.S. Pat. No. 4,450,755 which issued May 29, 1984 I disclosed a blower apparatus provided for the generation of an air curtain, screen or barrier. The apparatus of the aforemention patent includes a blower in the form of a plurality of blades arranged to describe a cylinder and a guide is provided which encircles the blower but which is open-ended and extends axially beyond the blower to generate an airstream, the width of which is greater than that of the blower. In addition in the apparatus of the aforementioned patent a deflector or interceptor plate is arranged which is coextensive with that portion of the guide which extends beyond the blower and which is coextensive with a portion of the blower in a moderate range thereof. The deflector or interceptor plate prevents air from circulating in an axial direction back into the blower and therefore improves the effectiveness of generation of the airstream which flows tangential out of the blower arrangement.
In the aforesaid patent the casing which houses the fan is provided with an intake opening covered with a screen and capable of admitting intake air This intake air flows into the casing at an angle which is perpendicular to the discharge of such air in the form of an air curtain or the like. In the apparatus of U.S. Pat. No. 4,450,755 the temperature of the air relies upon ambient conditions in the space in which the air blowing apparatus is installed. This means, since there is no provision for controlling the temperature of the air which is employed and discharged, that the temperature of the air curtain depends upon the temperature of the air which is fed into the system without any control being exercised thereupon. Accordingly it is frequently possible and even usual that the air of the air curtain which is generated is cold air which may be uncomfortable and humid and which is hardly likely to be ergonometrically qualified to offer the most suitable conditions for employees and the like who in the performance of whatever functions are assigned to them may have to pass through the opening which is being protected by the air curtain which is being generated.